Method for sizing corn



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Patented Apr.'l5, 1941 UNITED STATES PATENT OFFICE METHOD FOR SIZING CORN Oliver W. Steele, St. Louis, Mo., and Lester I. PiistenEl Paso, 111.

Application April 3, 1939, Serial No. 265,656

-1 Claim. (c1. 209- -235) The invention relates to new and useful improvements in sizing and separatirg methods and mechanism, and more particularly to such improvements in vibratory mechanisms for minutely and successively separating corn into a large number of accurately and closely dimensioned sizes.

Objects and advantages of the invention will be set forth in part hereinafter and in part will be obvious herefrom, or may be learned by practice with the invention, the same being-realized and attained by means of the instrumentalities and combinations pointed out .in the appended claims.

Theinvention consists in the novel parts, constructions, arrangements, combination and improvements herein shown'and described.

Fig. 3 is a transverse vertical section taken-on the line 3-3 of Fig. 1;

Fig. 4 is a perspective of a screen and screen frame;

Fig. 5 is a perspective of the means for returning the undersize from one screen to the head of the next, and of the discharge means for the oversize;

Fig. 6 is an enlarged diagrammatic showing of screen elements; and i Fig. 7 is a vertical section, partly diagrammatic, of a diflferent assembly of the screen elements and illustrating the steps of a method of size separation. v

.e invention is directed to provide a method and mechanism capacitated especially for sizing seed corn into a relatively large number of closely dimensioned sizes preparatory to use in mechanical planters. It is customary in large planting operations to employ mechanical corn planters, which will operate reliably only with closely sized seed com 50 as to insure that the proper number of grains, no more and no less, 5

are planted. The problem of pro-sizing the seed corn is both diflicult and important. To insure accurate dropping of the grains by the mechanical planter, without skipping or overplanting, the

ness, lengthand breadth of the kernels. The

. sizing is very close, and for the better and more expensive kinds of seed, such as hybrid seed com, the seed must be graded very closely, and desirably within V inch limits in both width and thickness. Under these requirements, from six to thirteen, or. more, different sizes of kernels may be found on the same car of corn, and a corresponding number of sizing operations must be performed to separate these sizes. Not only is uniform planting required in order that there may be no skipped hills or over-planted hills, but

'the cost 01' hybrid seed corn is many times that of open polinated varieties and accurate planting is necessary to prevent waste of seed.

Objects of the invention are to provide method and mechanism for accurately sizing the kernels as to both width and thickness within the close limits indicated and to provide simple, strong and inexpensive mechanism for eflecting such sizing; to provide for efl'ecting a complete sizing through the entire dimensional size ranges of the corn in one mechanism and by one continuous method andoperation; to provide for sequential screenings, certain'ot the screenings sizing the corn for width and other of the screenings sizing it for thickness; that is, after the kernels have'been classifiedto a plurality of predetermined close dimensions as to thickness, the kernels of each of these classes are then further classified to a plurality of predetermined close dimensions as towidth, thus providing a double dimensional close sizing for all .the kernels; to provide for subjecting the .corn to successive screenings on groups of screens, the one group having screen openings of difierent shape from those of another group, the screens in each group having screen openings of the same shape-but of different dimensions; more particularly to treat the kernels on a group of screens having oblong openings of gradually lesser width in successive screens, and then treating the separate size classifactions thus derived on a group of screens having circular openings of gradually lesser diameter in successive screens, thereby to obtain the required double-dimensional commercial sizes; to

a provide a mechanism of relatively large capacity and efliciency, especially as to the areas of screens employed, which is portable and simple to op- 0 crate, and to assemble and disassemble; which grains must be accurately pre-sized as to thickscreen, ;referably entirely from the headto the i mensions.

tall thereof, while undergoing the screening'operation, the oversize kernels being discharged from the tail end of the screen, the screen being relatively long and narrow. The screens are again to a similar sizing operation, and this is continued through the entire range of sizes.

One group of screens has screen openings of one shape, and another group has screen openings of another shape, the sizes of like shaped screen openings in a group being graduated in size to effect the desired classification, as by sixtyfourths of an inch, for the width or for-the thickness of the kernels. Means are also provided for taking off the doubly-dimensioned commercial sizes from the various screens at the points of completion of such sizing.

The method comprises treating the corn by successive screenings to separately and minutely size or classify it according to one dimension, for instance, thickness, and then treating each of those separate thickness classifications by successive screenings to separately and minutely size each separate thickness classification according to another dimension, for instance, width; that is, by successive screenings for thickness, the corn is separated into a plurality of very close and relatively minute sizes, which gives the necessary close classification as to thickness; these close and minute thickness sizes are then separately successively screened to effect a correspondingly very close and relatively minute sizing again as to width; the combined repeated close screenings for both dimensions giving the desired close and minute classification as to both thickness and width. This is carried the accompanying drawings, in Figs. 1 to 6 the structural features and vibrating means for a battery of screens are disclosed without. reference to the method, or the structural features which are especially employed in practicing the method. These latter are best shown in Fig. 7. In Figs. 1 to 6, a rigid supporting frame is provided, which may be conveniently made of structural angle bars, and is shown having at either side a plurality of vertically-disposed members I, 2 and 3 on one side, 4, 5, and 6 on the other, and these are fixed to and extend upwardly from floor rails 9 and I 0, and are connected together by horizontally-disposed bars 'I and 8 near the bottom part thereof and by cross-frame braces II and I2, having their ends at either side of the frame fixed to the vertical members i and 4 and 3 and 6. At their top ends the two sets'of vertical members are connected together by horizontally-disposedangle bar l3 at one side and M at the other, the fiat, horizontal top pieces of these angles serving to support the vibratable screen mechanism. The embodied means for positioning the screens either horizontally or at a longitudinal inclination comprises screw threaded rods I6, threaded into one end of the floor rails 6 and Ill. These level adjusting screw rods have hand wheels l1 and locking nuts IS.

A plurality of screen members or frames are disposed in superposed relation with intervenin means for returning the undersize from a screen above to the head of the screen next below, and these screen members or frames are mechanically connected or clamped together to constitute for operating purpose an integral structure. They are resiliently mounted on the supporting frame so as to be vertically vibrated as a unitary device, capacitated to repeatedly and successively separate out seed corn quickly and with precision within the required close size dimensions. As embodied, assembly screening units are provided having a two-put nestable frame, one part of the frame, that is, one of the detachable frames, carrying the screen and the other part or frame carrying the plate which returns the undersize toward thehea'dof the next screen.

out in practice by passing the corn over a suc- I classification for widths of kernels in the corn already classified for thickness of kernels, the classification thus being carried to any degree of closeness and 'minuteness as to both width and thickness of the kernels. The planting machine thus is supplied with kernels of the same size withinjsay, sixty-fourths of an inch in both di- It will be understood that the foregoing general description and the following detail description as well, are exemplary and explanatory of the invention, but are not restrictive thereof.

Referring now in detail to the embodiment of the invention illustrated by way of example in As embodied, a frame 2|, preferably rectangular, comprises side plates 22 and 23, a. head plate 24 and a plurality of bottom cross braces 25, the foraminate screen plate 26 being mounted within the frame and supported on the cross braces 25. There is no wall at the tail end of the screen, the oversize flowing off over the tail end of the screen; As embodied, the frame 22 is supported in nested relation upon a frame 3|, comprising side plates 32 and 33, a head end plate 34 and a tail end plate 35 extending across within and a short distancefrom-the tail end of the side plates 32 and 32. Abackwardly and downwardly inclined return plate 36 is mounted within the frame 3| its high end being at the cross wall 35, the plate being inclined downwardly toward the head end and terminating some desired distance short of the plate 66. The undersize of the screen 26 nextabove falls upon plate 36 and is supp rted and directed by the plate toward the head end of the next screen beneath. The length of the plate 36 will be such that the undersize will be delivered sufficiently near to the head of the 7 of thereturn frame, the head plate 24 of the screen framefrests on the head plate of the return frame, and the tail ends of the side plates 22 and 23 abut against the vertical edges 31 and 38 of the vertically-extending plates 39 and 49 of the return plate frame, the end of the screen 26 being just above the cross frame plate 35.

An end wall 43 connects across between the end plates 38 and 39 of the return plate frame, and between the tail end plate 55 and this wall '43 is an inclined plate 44 having its high end against the plate 40 and its low end at the bottom of the discharge opening 45 formed in the bottom part of end plate 58. The oversize corn flows from the screen 25 onto the inclined plate 44 and is discharged from the unit through opening 45.

The number of these two-part units to be employed will depend upon the required degree of dimensional minuteness of separation of the corn, as to thickness, breadth and length, and to meet commercial requirements with hybrid seed corn,

from six to thirteen units will ordinarily be used together. These are superimposed and clamped together and are vibrated as a mechanical unit. The embodied form of means for uniting or fixing the desired number of the units together comprises a plurality of cross beams 5|, 52, 53, 54 through which pass vertically-extending rods .56, 51, 58 and 59, the beams being supported on nuts 55 screw threaded on the rods, said rods at their upper ends pass through a rectangular top frame 60. The composite frame units 22, 32 are set one upon another, the bottom frame resting on the cross bars 5l54, and the top frame 6|! resting on the top of the uppermost screen unit frame 22. Nuts 6| are screw threaded on the'top ends of the rods 56-59, and are turned down to clamp the entire structure to form a solid vibrational unit.

The resilient mounting for the assembled screening units, as embodied, comprises a plurality of compression coil springs 59, III, II, 12 and 13, having their bottom ends nested in cups 14, 15,16, 11 and I8, fixed to the top faces of the respective horizontal frame members I! and I4. At either sideof the supporting frame, a

. plurality of flat springs 9|, 92 each have one end 83, 94 fastened to the top supporting frame members l3 and I4, and have their opposite ends 85, r 86 fastened to the under face of the top plate 50 a clamp screw 95 to regulate the flow of theunsized corn into the separator. Flexible connections 91 are connected to the openings 45 to carry away the oversize corn from the respective screens. The oversize from the lowermost screen fiows into the receiving hopper 99 and out at the The undersize from the lowermost" orifice 99. screen goes into the receiving hoppers I00 and HH and out through the orifices I02 and I03.

Any suitable form of vibratingmechanism may be employed, and as shown herein a vibrator I99 of the type known commercially as the Ajax- Shaler shaker," which comprises two oppositely rotating unbalanced rotors is mounted on a cross support Illl, carried on thetop frame 50 of the vibratable screen unit. The shaker is driven from a motor l ll, mounted .on a cross support H2, by means of a belt 3. The support 2 is supported from the stationary supporting frame, being riveted to the'horizontal top frame members I3 and I4 at either side.

In Fig. '7 is illustrated one commercial embodiment of the method and mechanism for classifying the corn both as to thickness and width to dimensions within sixty-fourths of an inch. By way of example, a highly efficient commercial arrangement of groups of screens with openings of two shapes in difierent groups and various sizes of each shape in the respective groups are shown in Fig. 7, the form of the openings being indicated at the left of the screens in said figure. Screens T and T have oval opens ings, respectively, x and x A", and effect the first classification for thickness. (It will be understood that the dimensions employed are merely exemplary of one form of commercial practice.) The oversize from the screen 'I' is taken off as 'reserve, and not generally used for planting. The oversize from screen T, which has now been classified for thickness, is directed for further classification as to width of kernels, as indicated by routing line 1' on to round hole screen W" having ,openings of and the undersize of that screen goes toscreen W with openings of %4" and the undersize from that to screen W with openings of The oversize of each of these screens is taken ofi as doublydimensioned commercial sizes. The undersize from screen I is directed for width classification to around hole screen W having openings of and the undersize from that screen goes to a screen Whaving round openings of these two screens sizing successively for width. The oversize from these screens are taken on as doubly-dimensioned commercial sizes as indicated by cs in Fig. 7. The oversize from screen 'I is directed as indicated by routing line 1, for

further sizing as to width together with the oversize from the screen T. The oversize from screen Tis directed to a battery of screens W to W for width sizing of the kernels. These screens having, respectively, round screen openings of for the first to for the last, and the oversize from each of these screens is taken offas doubly-dimensioned commercial sizes, as indicated as cs. Certain small sizes are taken off as culls at various points, as indicated by c. As here arranged, an undersize from the first double classification as to thickness and width is reclassified again both as to thickness and width, primarily as to thickness and then as to width. In routing the kernels after one classification, as to thickness, for the second classification, as to width, they are selectively routed so as to minimize the bulk of the undersize handled on various screens. 'It will be understood that the classifications as to'width and thickness relate to the two dimensions of the kernels otherthan their length, and the sequence may be varied so far as concerns the main features of the invention. The size of screen openings, the particular sequence of screens, both as to shape and size of openings, as exemplified in this particular commercial form, are exemplary of present preferred practice in applying the principles of the invention and are well adapted to closely size the kernels both as to width and thickness to meet present practical planting conditions with planters now in use.

The invention consists in the novel steps, sequences, elements and combinations as pointed out in the accompanying claim, and it will be understood that departures may be made from the specific forms shown and described without departing from the principles of the invention and without sacrificing its chief advantages.

What we claim is:

The method of sizing corn into a plurality of closely dimensioned sizes which comprises successively screening the corn and by the separate successive screenings closely dimensionally classifying the kernels as to thickness,,subjecting the corn so classified as to thickness to further sequential screenings to classify it as to width and taking 01! the oversize from the various screens of the last-mentioned series of screenings as doubly-dimensioned commercial sizes, said successive screening steps each comprising passing the kernels of corn substantially horizontally while subjecting said kernels to rapid vertical vibration projecting them upwardly from the horizontal path and causing them to fall vertically on end, thereby to efiect accurate screening as to width and thickness and to prevent clogging of the screens.

OLIVER W. STEELE. LESTER J. PFISTER. 

